The melanocytic and dysplastic nevi, in situ melanomas, superficially and deeply invasive melanomas and their lymph node metastases were analysed immunohistochemically for the amount of hyaluronan, its cell surface receptor CD44, hyaluronan synthases 1–3 and hyaluronidases 1–2. The gene discussed is HYAL1; the disease is dysplastic nevus.